Summary

The history of what we call molecular biology today is not just the story of DNA. Molecular biology emerged from and was supported by a multiplicity of widely scattered, differently embedded, and loosely, if at all connected experimental systems for characterizing living beings to the level of biologically relevant macromolecules. By implementing different modes of technical analysis, these systems created a new space of representation in which the central concepts of molecular biology gradually became articulated. The paper describes the establishment of the rat liverin vitro protein synthesis system of Paul Zamecnik and his group a the Collis P. Huntington Memorial Hospital of Harvard University between 1947 and 1952. Insofar as such systems orient the research activity, they may also prove helpful for the orientation of the historian. Experimental systems „have a life of their own”.